1 . Field
The following description relates to feature-based image processing technology, and more particularly, to an apparatus and a method for effectively extracting a feature descriptor from an image.
2 . Description of the Related Art
Technology for generating a feature descriptor based on a feature point extracted from an image, and matching the feature descriptor with another feature descriptor, is applied in various fields dealing with computer vision, such as content-based image retrieval, object recognition and detection, and video tracking, and is the subject of much research.
Recently, due to the introduction of smart phones, the amount of distributed multimedia content is explosively increasing, and demand for the above-mentioned technology associated with computer vision for effectively retrieving and consuming the multimedia content is increasing. Especially, due to inconvenience in inputting letters that is characteristic of smart phones, the need for content-based image retrieval technology that performs retrieval by inputting an image is increasing, and a retrieval application using the existing feature-based image processing technology is being actively created.
In the existing feature-based image processing technology, there are technology using a global feature and local feature-based image processing technology using a feature point. Here, the local feature-based image processing technology using the feature point has high accuracy, and thus is attracting much attention.
Scale-Invariant Feature Transform (SIFT) and Speeded Up Robust Features (SURF) are representative examples of the local feature-based image processing technology using the feature point. Such technologies extract a point for which change in a pixel statistical value is large, like a corner, as a feature point from a scale space, and extract a feature descriptor by using a relationship between the extracted point and a peripheral region. Such technology requires a number of operations and consumes a lot of memory in the process of extracting a feature descriptor and the process of matching, and thus is not appropriate for a mobile smart phone environment.
Moreover, even when a simple feature descriptor is required according to the purpose (content-based image retrieval and object detection in a specific category) and environment (mobile environment or high-performance personal computer (PC) environment) of a technical field of application, a number of operations are required to extract a single feature descriptor.